It was made public that Compound A having the chemical formula shown as below, since it displays an affinity and selectivity for muscarinic M3 receptors, is useful as an M3 receptor antagonist in prophylaxis or treatment of various M3 receptor-mediated diseases, particularly, urologic diseases such as urinary incontinence or pollakisuria in neurotic pollakisuria, neurogenic bladder, nocturnal enuresis, unstable bladder, bladder spasm, chronic cystitis, etc., respiratory diseases such as chronic obstructive pulmonary disease, chronic bronchitis, asthma and rhinitis, or digestive tract diseases such as irritable bowel syndrome also referred to as spastic colitis or diverticulitis (Patent document 1).

For the acid addition salt of Compound A, the above patent document 1 discloses only one salt, the hydrochloride salt of Compound A in Example 10, and no particular example is known regarding other acid addition salts except the hydrochloride salt described in the above patent document 1.
[Patent document 1] EP 0 801 067